日常Exception第二十九回：Flink启动异常之java.net.UnknownHostException: xxxx: Name or service not known

Posted 2023-01-19 善良勤劳勇敢而又聪明的老杨

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1、问题

        今天启动测试环境的flink内的服务，启动过程中发生了如下报错：

org.apache.flink.util.FlinkException: Failed to retrieve job list.
Caused by: java.net.UnknownHostException: fat: Name or service not known

 The program finished with the following exception:

org.apache.flink.util.FlinkException: Failed to retrieve job list.
	at org.apache.flink.client.cli.CliFrontend.listJobs(CliFrontend.java:449)
	at org.apache.flink.client.cli.CliFrontend.lambda$list$0(CliFrontend.java:430)
	at org.apache.flink.client.cli.CliFrontend.runClusterAction(CliFrontend.java:1002)
	at org.apache.flink.client.cli.CliFrontend.list(CliFrontend.java:427)
	at org.apache.flink.client.cli.CliFrontend.parseAndRun(CliFrontend.java:1060)
	at org.apache.flink.client.cli.CliFrontend.lambda$main$10(CliFrontend.java:1132)
	at org.apache.flink.runtime.security.contexts.NoOpSecurityContext.runSecured(NoOpSecurityContext.java:28)
	at org.apache.flink.client.cli.CliFrontend.main(CliFrontend.java:1132)
Caused by: org.apache.flink.runtime.concurrent.FutureUtils$RetryException: Could not complete the operation. Number of retries has been exhausted.
	at org.apache.flink.runtime.concurrent.FutureUtils.lambda$retryOperationWithDelay$9(FutureUtils.java:386)
	at java.util.concurrent.CompletableFuture.uniWhenComplete(CompletableFuture.java:760)
	at java.util.concurrent.CompletableFuture$UniWhenComplete.tryFire(CompletableFuture.java:736)
	at java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:474)
	at java.util.concurrent.CompletableFuture.completeExceptionally(CompletableFuture.java:1977)
	at org.apache.flink.runtime.rest.RestClient.lambda$submitRequest$1(RestClient.java:430)
	at org.apache.flink.shaded.netty4.io.netty.util.concurrent.DefaultPromise.notifyListener0(DefaultPromise.java:577)
	at org.apache.flink.shaded.netty4.io.netty.util.concurrent.DefaultPromise.notifyListenersNow(DefaultPromise.java:551)
	at org.apache.flink.shaded.netty4.io.netty.util.concurrent.DefaultPromise.notifyListeners(DefaultPromise.java:490)
	at org.apache.flink.shaded.netty4.io.netty.util.concurrent.DefaultPromise.setValue0(DefaultPromise.java:615)
	at org.apache.flink.shaded.netty4.io.netty.util.concurrent.DefaultPromise.setFailure0(DefaultPromise.java:608)
	at org.apache.flink.shaded.netty4.io.netty.util.concurrent.DefaultPromise.tryFailure(DefaultPromise.java:117)
	at org.apache.flink.shaded.netty4.io.netty.channel.nio.AbstractNioChannel$AbstractNioUnsafe.connect(AbstractNioChannel.java:284)
	at org.apache.flink.shaded.netty4.io.netty.channel.DefaultChannelPipeline$HeadContext.connect(DefaultChannelPipeline.java:1342)
	at org.apache.flink.shaded.netty4.io.netty.channel.AbstractChannelHandlerContext.invokeConnect(AbstractChannelHandlerContext.java:548)
	at org.apache.flink.shaded.netty4.io.netty.channel.AbstractChannelHandlerContext.connect(AbstractChannelHandlerContext.java:533)
	at org.apache.flink.shaded.netty4.io.netty.channel.CombinedChannelDuplexHandler$DelegatingChannelHandlerContext.connect(CombinedChannelDuplexHandler.java:495)
	at org.apache.flink.shaded.netty4.io.netty.channel.ChannelOutboundHandlerAdapter.connect(ChannelOutboundHandlerAdapter.java:51)
	at org.apache.flink.shaded.netty4.io.netty.channel.CombinedChannelDuplexHandler.connect(CombinedChannelDuplexHandler.java:296)
	at org.apache.flink.shaded.netty4.io.netty.channel.AbstractChannelHandlerContext.invokeConnect(AbstractChannelHandlerContext.java:548)
	at org.apache.flink.shaded.netty4.io.netty.channel.AbstractChannelHandlerContext.connect(AbstractChannelHandlerContext.java:533)
	at org.apache.flink.shaded.netty4.io.netty.channel.AbstractChannelHandlerContext.connect(AbstractChannelHandlerContext.java:517)
	at org.apache.flink.shaded.netty4.io.netty.channel.DefaultChannelPipeline.connect(DefaultChannelPipeline.java:978)
	at org.apache.flink.shaded.netty4.io.netty.channel.AbstractChannel.connect(AbstractChannel.java:253)
	at org.apache.flink.shaded.netty4.io.netty.bootstrap.Bootstrap$3.run(Bootstrap.java:250)
	at org.apache.flink.shaded.netty4.io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:164)
	at org.apache.flink.shaded.netty4.io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:472)
	at org.apache.flink.shaded.netty4.io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:500)
	at org.apache.flink.shaded.netty4.io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989)
	at org.apache.flink.shaded.netty4.io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
	at java.lang.Thread.run(Thread.java:748)
Caused by: java.util.concurrent.CompletionException: java.net.UnknownHostException: fat: fat: Name or service not known
	at java.util.concurrent.CompletableFuture.encodeThrowable(CompletableFuture.java:292)
	at java.util.concurrent.CompletableFuture.completeThrowable(CompletableFuture.java:308)
	at java.util.concurrent.CompletableFuture.uniCompose(CompletableFuture.java:943)
	at java.util.concurrent.CompletableFuture$UniCompose.tryFire(CompletableFuture.java:926)
	... 28 more
Caused by: java.net.UnknownHostException: fat: fat: Name or service not known
	at java.net.InetAddress.getLocalHost(InetAddress.java:1505)
	at sun.nio.ch.SocketChannelImpl.connect(SocketChannelImpl.java:647)
	at org.apache.flink.shaded.netty4.io.netty.util.internal.SocketUtils$3.run(SocketUtils.java:91)
	at org.apache.flink.shaded.netty4.io.netty.util.internal.SocketUtils$3.run(SocketUtils.java:88)
	at java.security.AccessController.doPrivileged(Native Method)
	at org.apache.flink.shaded.netty4.io.netty.util.internal.SocketUtils.connect(SocketUtils.java:88)
	at org.apache.flink.shaded.netty4.io.netty.channel.socket.nio.NiosocketChannel.doConnect(NioSocketChannel.java:315)
	at org.apache.flink.shaded.netty4.io.netty.channel.nio.AbstractNioChannel$AbstractNioUnsafe.connect(AbstractNioChannel.java:248)
	... 18 more
Caused by: java.net.UnknownHostException: fat: Name or service not known
	at java.net.Inet6AddressImpl.lookupAllHostAddr(Native Method)
	at java.net.InetAddress$2.lookupAllHostAddr(InetAddress.java:928)
	at java.net.InetAddress.getAddressesFromNameService(InetAddress.java:1323)
	at java.net.InetAddress.getLocalHost(InetAddress.java:1500)
	... 25 more

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2、解决办法

        根据提示内容分析，是启动过程中，flink无法识别 fat 这个hostname。所以，直接按如下步骤操作即可：

1. 第一步，使用命令：vim /etc/hosts，在编辑页面中，加上你的映射ip及host名称，如：192.168.*.* fat
2. 第二步，使用命令：/etc/init.d/network restart，刷新hosts文件，使其生效

         按照如上步骤，再次重启flink服务，就不回再报错啦！！！